Burning brick



Patented Feb. 1, 1938 UNITED STATES PATENT. OFFICE No Drawing.Application February 24, 1937, Serial No. 127,402

8 Claims.

This invention relates to improvements in methods of producing blackbrick and other ceramic products.

Manufacturers have long tried to make black brick by different methodsbut no quantity of satisfactory brick'was produced by these methods.

One of these previous methods included coating bricks with manganesecompounds or mixing manganese compounds with the clay before burning.Another method was known as flashing. In these treatments toproduceblack brick, the manufacturers always maintained too high a temperaturein the kiln to get the desired results.

According to my invention I produce brick in commercial quantities whichis black on all faces and through and through. To produce these blackbricks, I finish burning the brick in the usual way and then reduce thetemperature to about 1200" F. or to about of the normal burningtemperature used in manufacturing brick. Then I fill up the fire boxeswith soft coal with as high a volatile content as obtainable and burnthe soft coal with an insufficient supply of air in order to producelarge quantities of smoke. This smoke is circulated through the kiln.When all the smoke has burned out of the soft coal or the coal hascoked, part of the coke is removed and more soft coal is added and thisoperation is repeated until a sample taken out and cooled shows that thebrick is black. Then the fire is raked out as fast as possible and thebrick is cooled quickly. The resulting product is a black brick which isblack on all faces and through and through. Instead of soft orbituminous coal I may use other coals or fuels which form heavy or blacksmoke when insufficient air is supplied for combustion, as for example,fuel oil.

My invention will now be more specifically set forth. My process ofproducing black brick starts with the brick which is still hot after theusual burning operations. That is, the brick is finished by burning inany of the usual ways and my process starts here at the completion ofthe burning and while the brick is at the high temperature of about 1500F. to 1950 F, I start by cutting off the supply of fresh fuel to thefire boxes and allowing cold air to pass over the fires into the kiln.Any other method of cooling the kiln may be used. Sufficient fire iskept in the furnaces to ignite the soft coal which is later added whenthe kiln is ready for the smoking operation.

When the temperature of the kiln and brick has been reduced to about 900F. or not over 1200 F. the fire boxes are filled up with bituminous coaland as each fire gets under way, the draft below the grate is shut offand very little or no air is allowed to pass over the top of the fire.The damper .in the stack or stacks is lowered or the draft is shut offsufiiciently to draw .the smoke only from the furnaces and circulate itvery slowly through the kiln and in contact with the hot brick.

When all the smoke has burned out of the coal or fuelor the coal iscoked, part of the hot coke is raked from the fires but sufficient .hotcoke is left in the fire boxes to ignite a new batch .of bituminous coalor fuel which is then added. After this new batch of coal is coked, theoper ation of removing part ofthe coke and coaling up the fires withbituminous coal is repeated as often as necessary to insure smoking thebrick to complete blackness throughout. In certain instances it willtake about hours of smoke treatment to obtain my black brick product.This time of treatment may be varied within limits to suit differentconditions or to produce slightly different effects.

During the smoking treatment the temperature of the brick and kiln mayrise from about 900 F. or about 1200 F. to not over about 1400" F. Whenthe smoking period is completed, the fire in all the fire boxes is rakedout or removed as quickly as possible. Then the kiln doors are openedpartly and after the doors have been open for about two hours and thetemperature of the brick reduced to about 1100 F., ablower is put infront of one door and air is blown into the kiln to blow the hot airout. This is continued until no red hot brick can be seen and until thetemperatureof the brick is reduced to about 500 F. The-blower willnormally be in operation about 8 hours. In .some instances the kilndoors may .be opened wide at the beginning of the cooling operation toobtain faster initial cooling. Any method of quick cooling may be usedthat will not damage the product.

The brick is then removed from the kiln in the usual manner and thebrick produced are black on all the faces and through and through.

In my method it is important to reduce the temperature of the burnedbrick before proceed ing with the smoking treatment and it is alsoimportant to rapidly cool the brick after the smoking treatment. Thislatter cooling is done more quickly than the usual methods of coolingafter burning brick in the usual Ways. Generally after completion of thesmoking operation the brick is cooled from about 1400 F. to about 500 F.in about 10 to 12 hours.

As above set forth, my method starts with brick immediately after theburning has been finished in the usual ways. This method applies to andis effective in making black brick regardless of the mineral contents ofwhich the brick is made. Any material that can be burned into brick orceramic products can be turned black by this process. An analysis of oneexample of ordinary brick made by usual methods will now be given but itis to be expressly understood that the same does not form part of myinvention, nor is my invention to be restricted thereto as the exampleis merely included to give one method of burning brick preparatory tothe application of my process thereto. Other brick mixtures may be usedand other temperatures used, it being only necessary that the burning ofthe brick be substantially completed.

Per cent Silica 61.35 Iron 10.16 Aluminum 26.46 Lime 0.32 Magnesium 0.71Sulphur 0.20

The brick is stacked into a kiln and the fire started. The kiln is fireduntil the finishing temperature is obtained and this temperature ismaintained as long as necessary to complete the burn. After the brick isburned, the temperature of the brick and kiln is reduced to about 900 F.or not over 1200 F. The brick is then ready for my process and istreated in the way as above given.

Brick ,or similar material burned in other ways may be treated accordingto my method to produce black brick or the like. The temperatures givenby me may be varied Within limits and also the smoking period may bevaried.

When the smoking is completed and the kiln is cooled sufficiently tohandle the brick, they are ready for sale or shipments. There ispractically no soot deposit on the brick when finished smoking, and notany more than when the brick is burned in theusual method. The brick areblack through and through and all faces are jet black.

It salt glazed brick are desired, it is only necessary to mix with thefuel each time the smoke fire is renewed, approximately six (6) poundsof coarse salt to each fire box, and smoke in the same manner asdescribed for jet black brick. This method will produce a glazed orglossy black brick.

It is to be understood that the foregoing example is given only by wayof illustration and that the same may be modified in many particularswithout departing from the spirit of my invention, and my inventionapplies to ceramic products made by any of the different processes ofmanufacture, such as stiff mud, soft mud, hand made or any otherprocess. The wood brick or brick product is used throughout merely forthe sake of brevity.

What I claim is:

1. A method of the character described for producing black brick whichcomprises cooling brick in a kiln from the burning high temperature toabout one-half the burning high temperature, subjecting the cooled brickto an extended period of smoking, and then cooling the smoked brickquickly.

2. A method of the character described for producing black ceramicarticles which comprises cooling ceramic articles in a kiln from theburning temperature to a lower temperature, subjecting such articles toa smoky atmosphere for an extended period of time, and then cooling thesmoked articles quickly.

3. A method of; the character described for producing black brick whichcomprises cooling brick in a kiln from the finishing temperature toabout 900 F. or not higher than 1200 F., subjecting such brick tofreshly formed smoke from burning bituminous fuel with an insuificientsupply of air for complete combustion, continuing the smoke treatment ofthe brick for a period sufiicient to produce black brick and thencooling the smoked brick quickly.

4. A method of the character described for pro ducing black brick whichcomprises providing brick at about 900 F. and not above 1200 F. in aconfined space, subjecting such brick to a smoky atmosphere for anextended period of time, circulating the smoky atmosphere in theconfined space, and then cooling the smoke brick by reducing thetemperature quickly from the very beginning of the cooling operationafter smoking.

5. A method of the character described for producing black brick whichcomp-rises providing burned brick at about 1100 F. to about 1200 F. in aconfined space, subjecting such brick for an extended period of time tohot smoke freshly formed by burning bituminous coal with a supply of airinsufficient for complete combustion, circulating the smoke in suchconfined spacein contact with the brick, and then cooling the smokedbrick by quickly reducing the temperature at the beginning of thecooling operation.

6. A method of the character described for 7. A method of the characterdescribed for pro ducing black brick which comprises providing burnedbrick at about ll00 F. to about 1200" F. in a confined space, subjectingsuch brick for an. extended period of time to hot smoke, circulating thesmoke in such confined space in contact with the brick, and then coolingthe smoked brick by quickly reducing the temperature thereof.

8. A method of the character described for pro ducing black brick whichcomprises cooling brick in a kiln from the finishing temperature toabout 900 B2, or not higher than 1200 F., subjecting such brick tofreshly formed smoke from burning bi uminous fuel with an insufiicientsupply of air for complete combustion, continuing the smoke treatment ofthe brick in a rising temperature Whose limit is 1400" F. for a periodsufiicient to produce black brick, and then cooling the smoked rickquickly from the highest temperature reached by said brick during thesmoking operation.

THOMAS B. DREI-IER.

